Liquid phase electron-beam-induced deposition on bulk substrates using environmental scanning electron microscopy

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Environmental scanning electron microscopy (ESEM) commonly uses gases like water vapor for imaging.
• This gas introduction capability can be leveraged for electron-beam-induced deposition (EBID) using liquid precursors.
• Developing precise, cell-less deposition methods is crucial for advanced microfabrication.

Purpose of the Study:

• To explore novel cell-less in situ deposition techniques for metal structures.
• To investigate the role of surfactants in improving pattern fidelity and deposit purity.
• To demonstrate the deposition of silver (Ag) and copper (Cu) structures.

Main Methods:

• Utilized two distinct cell-less in situ deposition methods within an ESEM.
• Method 1: In situ hydration of solid metal precursors.
• Method 2: Insertion of liquid metal precursor droplets via a capillary injection system.
• Incorporated surfactants into liquid precursors to study their effect on deposition.

Main Results:

• Successfully deposited silver (Ag) and copper (Cu) structures using both methods.
• Demonstrated that surfactants significantly enhance pattern replication accuracy.
• Confirmed that surfactants do not compromise the purity of the deposited metal.
• Observed a drastic reduction in droplet contact angle (below ~10°) with surfactant addition.

Conclusions:

• Cell-less in situ deposition in ESEM is a viable technique for metal structure fabrication.
• Surfactants are critical for achieving high-fidelity pattern transfer in liquid-phase EBID.
• These methods offer a promising route for fabricating pure metal nanostructures with controlled morphology.